Tanning.



ERNST SCHW'ARZ, OF BERLIN, AND LUUIS BLANGEY, 0F

ASSIGTTORS Ti) MANNHEIM, GERMANY,

BAIDISGHE .AIQIILIN 65 S035. FAJBIEHK, 0F IfUDV/YIGSHAFEIT-UN- THE-RHINE. GERMANY, A. C(IREBOEATIDN.

Ho Drawing.

'1' 0 all whom it may concern;

Be it known that: we, ERNST SGHWARZ and Louis BLANGEY, citizens of the German Empire ,and the Swiss Republic, respectively resid ng at Berlin; and Mannheim, respectively; Germany hm invented new and use ful Improvements in Tanning, of: which the following is a specification.

We have found that We can convert hides into a leather having good properties by treating the hides with a hath containing a cai'bzizole sulfonic acid. Under this term we comprise the monosulfonic and polysuifOIliC acids of carhezole itseif or of carhezoie derivatives or of crude carhazole or of Waste products containing cnrhazoie e chief constituent. The said sulfonic acids can be employed either alone or in the form of mixtures of several sulfonic acids and in either case other tanning materials or other bodies can he added. The said sulfonic acids can he directly employed in the free state or their salts especially their alkaii 'saits, can he used with an addition of an acid.

The following is an exzunple of how the invention can he carried out out the invention is not, confined to this example. Z V

Dissolve 70 parts of crirhezolc monosulfonic acid sodium salt; water, acidify with 70 parts of dilute sul} furic acid of 10%, introduce the hides de- S iecii'icetiozi of Letters Patent.

in 1000 parts of l fisiieiiized Dec, 33? a iipplicalic filed April 2?, 1917. Serial E0. lfifififll.

prived of lime by means of a bisulfife solution and treat until they are thoroughly tanned. Then the leather is washed and fattcd is usual.

in en analogous manner the process can be carried out by preparing the tanning bath with other carbazole sulfonic acids, for i stance such as carhazoie disulfonic acid so dium salt or the mixture of sulfonic acids obtained by sulfonating pure or crude csrlmzole r. 1. the nutlii'acene waste products obtained by purifying crude HHtlU'ECBDQ OI' sulfcnic acids of chlor-carbazoie or N- methyl carbazole and so on.

What we claim is:

1. The process of tanning which comprises treating hides in 2]. bath containing a cerhezole sulfonic acid. e

2. The process of tanning which comprises treating hides in a bath containings plu rality of carbazole sulfonic acids.

3. The process of tanning which comprises treating hides in a hath containing sulfonmed crude carlcazol e.

s new irsicleof manufacture a i iI 1.ii'fi" ]'lQ as a tanning constituent console sulioiiic acid, in testimony whereof we have hereunto our hands 7 ERNST SCHWARZ. LOUIS BLANGEY. 

